Conventionally, a recording device system in which a recording device records a plurality of data items transmitted from a plurality of control units which are interconnected by a multiplex connection line in an in-vehicle LAN is known. The control units constitute the nodes of the in-vehicle LAN. For example, refer to Japanese Laid-Open Patent Application No. 2002-330149.
In a case of the system of Japanese Laid-Open Patent Application No. 2002-330149, when the vehicle starts operation, the plurality of data items addressed to the recording device are outputted, at a predetermined timing (or periodically), to the in-vehicle LAN from the plurality of control units (such as an engine control unit, an ABS control unit, and a door control unit). The recording device collects and records the plurality of data items.
However, the above-mentioned system does not take into consideration the rule of how or in what sequence the recording device should collect the plurality of data items of different kinds sent from the plurality of control units. For example, when a malfunction diagnosis of the vehicle is performed, it is necessary to collect the plurality of data items which are outputted in the almost same period. However, if the individual rules between the recording device and the respective control units are inherently defined, the rule of collecting the plurality of data items of different kinds becomes complicated, and the versatility of the system is lost. As the result, the collection of the plurality of data items of different kinds becomes difficult.